Valve opening system of internal combustion engine

摘要

A valve mechanism of an internal combustion engine is provided which includes a camshaft that produces drive force for opening and closing a plurality of shut-off valves provided on a combustion chamber. This valve mechanism has a rocker shaft supported at its opposite ends by a pair of rocker shaft supports onto a cylinder head, and first and second rocker arms that are supported by the rocker shaft between the rocker shaft supports such that these rocker arms are movable with respect to each other. The first rocker arm has at one end portion thereof a point of force that receives the drive force from the camshaft, and the second rocker arm has a point of application for driving part of the shut-off valves, at one end portion that is opposite to the point of force of the first rocker arm with respect to an axis of the rocker shaft. The point of application of the second rocker arm is located opposite to the point of force of the first rocker arm, such that an imaginary plane, which includes a middle point of the rocker shaft between the rocker shaft supports and orthogonal to the axis of the rocker shaft, is interposed between the point of application and the point of force.